title: Clinical significance of synthesized posterior/right-sided chest lead electrocardiograms in patients with acute chest pain.
abstract: BACKGROUND
  12-lead electrocardiograms (ECGs) provide insufficient information for the accurate diagnosis of posterior and/or right ventricular acute myocardial infarction (AMI) in patients with acute chest pain. Posterior chest leads (V7-V9) and/or right-sided precordial leads (V3R-V5R) provide important information from those specific areas, but these additional ECGs are not routinely recorded because of the time-consuming procedure involved. The purpose of the present study was to evaluate a newly developed system to synthesize these 6 additional lead ECGs non-invasively using standard 12-lead ECG information.
  
  
  METHODS
  Thirty patients (25 men, 5 women; mean age: 65 ± 11 years) complaining of acute chest pain were enrolled. Standard 12-lead and V3R, V4R, V5R, V7, V8, V9 lead ECGs were successively recorded and compared with synthesized ECGs mathematically derived from standard 12-lead signals.
  
  
  RESULTS
  The synthesized and actual ECG waveforms were almost identical, and there were significant correlations in ECG variables, including the P, QRS, and T waves (correlation coefficients about total 1-cycle signals: 0.97 in V3R; 0.93 in V4R; 0.88 in V5R; 0.98 in V7; 0.92 in V8; and 0.88 in V9, p<0.001). Both in patients with AMI (N=16) and in patients with ST elevation at the extended leads (N=8), significant correlations were also found (correlation coefficients were over 0.88 at all leads, p<0.001). The reproducibility of the ST segment was as good as that of the other ECG variables, even in patients with significant ST elevation due to posterior and/or right ventricular AMI.
  
  
  CONCLUSIONS
  Synthesized posterior and right-sided precordial lead ECGs appear to be highly reliable and useful in the rapid diagnosis of AMI, especially in the early detection of posterior and/or right ventricular involvement, thereby alleviating patient distress.
authors.affiliation: Division of Cardiology, Hepatology, Geriatrics, and Integrated Medicine, Department of Internal Medicine, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan. tkkt@nms.ac.jp
authors.forename: Takao
authors.initials: T
authors.lastname: Katoh
authors.forename: Akira
authors.initials: A
authors.lastname: Ueno
authors.forename: Keiji
authors.initials: K
authors.lastname: Tanaka
authors.forename: Jiro
authors.initials: J
authors.lastname: Suto
authors.forename: Daming
authors.initials: D
authors.lastname: Wei
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001018:Aortic Diseases / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D002318:Cardiovascular Diseases / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D002637:Chest Pain / Q000209:etiology / Q000503:physiopathology*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006330:Heart Defects, Congenital / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity